One of the enduring curiosities about Gretzky’s career is it can support just about any argument, even those directly opposite. He can be called the game’s greatest player and ambassador – as will be eloquently done by former Globe and Mail sportswriter Al Strachan in this fall’s 99: Gretzky, His Game, His Story – and he can also be said, somewhat tongue in cheek, to have been the worst thing possible to happen to the game.

It was Gretzky’s trade from the Edmonton Oilers to the Los Angeles Kings 25 years ago this week – amidst charges of everything from greed to deceit to suggestions his wife, Janet, was hockey’s Yoko Ono – that inspired some ill-considered expansion into alien markets.

It was his brilliance and the Oilers’ domination in the 1980s that caused rule changes to hammerlock scoring, that begat the dreadful neutral-zone trap, that led to professional hockey becoming absurdly overcoached.

It cannot be debated, however, that he came along at an important time for Canada. The 1972 Summit Series – played the season after the 10-year-old wunderkind from Brantford, Ont., first gained national attention by scoring 378 goals for the Nadrofsky Steelers – was the first suggestion Canadians might be fairly challenged in their national game.

The season following Canada’s humiliating 8-1 whipping by the Soviets in the 1981 Canada Cup, a tournament in which the 20-year-old Gretzky was Canada’s top scorer, he stunned the NHL by scoring an unprecedented 212 points and was, undeniably the greatest player in the game. In the 1987 Canada Cup, a fully mature Gretzky led Canada to a triumphant wound-licking by defeating the Russians in a thrilling three-game final.

The late Igor Dmitriev, one of the coaches of that Soviet team, said at the time “Gretzky is like an invisible man. He appears out of nowhere, passes to nowhere, and a goal is scored.” It was a perfect summation of a unique talent.

He continues in a very Canadiana-ish vein, while Duhatschek offers a different sort of modern take...

The Gretzky deal fundamentally and forever changed the perception of the NHL trade market. For years, there was a notion some players – because of their skill levels or their impact on the team or their ties to the community – were untouchable … so don’t even bother inquiring.

After Gretzky was shipped out, the view changed. At every subsequent NHL trading deadline, someone would venture: “If Wayne Gretzky can get traded …”

The unfinished thought was “… anyone can.”

It also spawned a new way of assessing player movement.

Nowadays, people speak reverentially about that rare and almost obsolete transaction known as a “hockey” deal. Prior to the Gretzky trade, virtually every NHL deal was a hockey deal. Teams swapped personnel and the assessments – who won and who lost – were usually measured by what subsequently occurred on the ice.

Now, with a salary cap that governs a team’s expenditures, the contract status of the players involved in a deal frequently trump what they might bring to a team on the ice.

Gretzky’s move to L.A. also helped fuel NHL salary escalation. McNall quickly made Gretzky the highest-paid player in the game – and that in turn started the ball rolling in terms of increasing player compensation across the board.

Before he continues as well.